This project is designed to investigate fundamental questions regarding the sensory and cognitive basis of the olfactory evoked potential (OEP), and the application of the OEP in clinical settings where an objective index of sensory function has importance. The project will begin with parametric manipulation of stimulus and recording variables to elicit the most consistent, reliable, and robust OEP recordings. Once this has been accomplished, a study will commence to determine the capability of the individual person's OEP to indicate the functional olfactory status of that individual. This goal will be approached systematically by studying normal individuals.of various ages, including the elderly, and patients from the Nasal Dysfunction Clinic at the University of California, San Diego Medical Center who are known from precise psychophysical testing to be hyposmic, parosmic, phantosmic, or anosmic. State-of-the-art psychophysical measures of olfactory function will be utilized to characterize individuals and then compare OEPs for those individuals l) with their function measured psychophysically, and 2) against age- normative average OEP for the group, which will be collected. The individual's OEP will be compared to the auditory and visual evoked potentials for anosmics, hyposmics, and normals. Because one of the ultimate goals of this project is to use the OEP in various clinical populations who show olfactory dysfunction, including Alzheimer's patients, the feasibility of using the technique with demented individuals will be investigated. In the latter phase of the project, the possibility of recording an olfactory P3, using a variant of the "odd-ball paradigm," and its usefulness in clinical populations will be investigated.